1. Field of the Invention
The present invention relates to a system for administering a gaseous mixture in a single continuous dose to a patient for medical treatment. More specifically, this invention relates to a device for administering a single dose of gas to a patient by means of a control valve that once turned to the “on” position cannot be turned to the “off” position by the patient.
2. Known Art
In the treatment of patients with asthma it has been discovered that a gaseous mixture of helium and oxygen, referred to herein as a “heliox” mixture, is therapeutically beneficial. During an asthmatic attack, the bronchioles of the lungs become constricted and blocked with mucus. This constriction and subsequent blockage of the bronchioles causes the patient suffering the attack to be deprived of oxygen which can lead to discomfort, brain damage, or even death if not treated. It has been discovered that a heliox mixture consisting solely of helium and oxygen (usually about 80% helium and about 20% oxygen) will help increase the oxygen absorption into the restricted and blocked bronchioles of the lungs. Garret U.S. Pat. No. 6,001,332 contends that because the density of helium is lower than that of oxygen, a heliox mixture is more readily absorbed by restricted bronchioles than pure oxygen. It is believed that when oxygen is mixed with helium in a heliox mixture, the mixture of the gasses will allow more oxygen to enter the lungs and alleviate a severe asthmatic attack.
Despite heliox treatment's properties to increase oxygen absorption of the lungs there remains a potential problem when using heliox. After a patient has begun a heliox treatment the symptoms of the asthmatic attack cease or are reduced almost immediately. This causes the patient to feel as if the treatment is no longer needed and the patient or other person treating the patient (usually an Emergency Medical Technician or another person assisting the patient) may discontinue the treatment by shutting off the device that supplies the treatment. When this is done the sudden absence of helium from the patient causes the return of an acute asthmatic attack, in that while the bronchioles were able to absorb more oxygen with the heliox mixture, they are still in a contracted and blocked state. The sudden removal of helium from the patient's lungs may cause the patient to lapse into an acute asthmatic attack, the severity of which may be fatal. Thus, in order for a heliox treatment to be effective, it should be administered continuously in a single dose until a qualified medical specialist can determine that the heliox is no longer needed or that other treatment may be safely administered.
There are known regulators available for administering a heliox treatment, or other gaseous treatment to patients. These known devices typically have the drawback that either the patient or another person assisting the patient has complete control of the ability to turn the regulators on or off or to adjust flow rate. For example, Lewis U.S. Pat. No. 6,302,106 contends a system designed to be adaptable for use with a heliox mixture, the regulation being readily adjustable to vary the flow rates of dispensing of the gaseous mixture. Also, pending published application U.S. application 200010035183 to Hill filed on Nov. 1, 2001, provides for a system of ventilation with a maximum degree of flexibility allowing the system to be turned on or off if desired.
While in certain situations the ability to vary the flow rate of the gaseous mixture to the patient may be desirable, this is believed to be undesirable for patients receiving a heliox treatment who are suffering from an acute asthmatic attack as mentioned above, if the heliox treatment is suddenly stopped by the patient who feels it is safe to do so, the sudden lack of or reduction of heliox treatment might cause the patient to relapse into serious asthmatic attack. There exists a need then in the art of breathing regulators and gas distribution systems that prevents a patient from discontinuing or altering the flow rate of the life saving treatment of heliox, and provides a heliox treatment in a safe, single, continuous dose.